Diff: MAX30100_BeatDetector.h

Revision:

0:010b908e2187

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/MAX30100_BeatDetector.h	Fri Nov 25 00:52:54 2016 +0000
@@ -0,0 +1,64 @@
+/*
+Arduino-MAX30100 oximetry / heart rate integrated sensor library
+Copyright (C) 2016  OXullo Intersecans <x@brainrapers.org>
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef MAX30100_BEATDETECTOR_H
+#define MAX30100_BEATDETECTOR_H
+
+#include "mbed.h"
+#include <stdint.h>
+#include <algorithm>
+
+#define BEATDETECTOR_INIT_HOLDOFF                2000    // in ms, how long to wait before counting
+#define BEATDETECTOR_MASKING_HOLDOFF             200     // in ms, non-retriggerable window after beat detection
+#define BEATDETECTOR_BPFILTER_ALPHA              0.6     // EMA factor for the beat period value
+#define BEATDETECTOR_MIN_THRESHOLD               20      // minimum threshold (filtered) value
+#define BEATDETECTOR_MAX_THRESHOLD               800     // maximum threshold (filtered) value
+#define BEATDETECTOR_STEP_RESILIENCY             30      // maximum negative jump that triggers the beat edge
+#define BEATDETECTOR_THRESHOLD_FALLOFF_TARGET    0.3     // thr chasing factor of the max value when beat
+#define BEATDETECTOR_THRESHOLD_DECAY_FACTOR      0.99    // thr chasing factor when no beat
+#define BEATDETECTOR_INVALID_READOUT_DELAY       2000    // in ms, no-beat time to cause a reset
+#define BEATDETECTOR_SAMPLES_PERIOD              10      // in ms, 1/Fs
+
+
+typedef enum BeatDetectorState {
+    BEATDETECTOR_STATE_INIT,
+    BEATDETECTOR_STATE_WAITING,
+    BEATDETECTOR_STATE_FOLLOWING_SLOPE,
+    BEATDETECTOR_STATE_MAYBE_DETECTED,
+    BEATDETECTOR_STATE_MASKING
+} BeatDetectorState;
+
+
+class BeatDetector
+{
+public:
+    BeatDetector();
+    bool addSample(float sample);
+    float getRate();
+    float getCurrentThreshold();
+
+private:
+    bool checkForBeat(float value);
+    void decreaseThreshold();
+
+    BeatDetectorState state;
+    float threshold;
+    float beatPeriod;
+    float lastMaxValue;
+    uint32_t tsLastBeat;
+    Timer t;
+};
+
+#endif
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